Modeling seawater intrusion in the Portorecanati aquifer, Italy
P. Teatini, G. Gambolati
Dept. Mathematical Methods and Models for Scientific
Applications, University of Padova, Padova, Italy
M. Gonella
Med Ingegneria S.r.l., Ferrara, Italy
B. Brunone, M. Ferrante
Dept. Hydraulic and Structural Engineering, University of Perugia, Perugia,
Italy
S. Marconi
AST S.p.A. Recanati, Italy
ABSTRACT
Seawater intrusion is an important environmental problem for coastal aquifers of
the Adriatic Sea coastland. In the shallow confined aquifer of the Potenza river
plain located in the Portorecanati Municipality, there has been a recent large
increase of both the private pumping wells used for irrigation and the withdrawal
rate from a well-field managed by the local Water Distribution Company since the
1980s. This has resulted in a significant lowering of the water table with a
consequent deterioration of groundwater quality. In the early 1990s, seawater
intrusion was so pronounced as to require the shutdown of the well-field and the
development of a new field 300 m inland, whose water quality has been
deteriorating despite the much reduced pumping rate. In order to investigate the
contamination process, a modeling study supported by in situ investigations is
performed. A bidimensional finite element model of saturated flow and transport
is developed to simulate the contamination of the coastal aquifer. The overall
model is calibrated against available records and simulations are performed to
analyze the interaction between natural recharge and agricultural/civil pumpage,
and the saltwater distribution in the subsurface. The fresh-saltwater front
induced by the aquifer overdraft at the old well-field turns out to be
reproduced reasonably well, whereas the contamination caused by the new field
is found hard to correlate to the saltwater encroachment.
